It's part of a (very famous) quote from Bladerunner. However the stars Betelgeuse and Bellatrix are both positioned at the hunter's shoulders in the constellation of Orion, so the quote probably refers to one them.

I suppose it would be, if you are talking about the constellation of Orion, which is associated with the character in Greek Mythology of the same name. The major body of the constellation is made up of 6 different stars. If you take a look at the pictures on this page, you can see about where the shoulders should be: https://en.wikipedia.org/wiki/Orion_(constellation) However, this would depend on the context of where you heard the phrase "The Shoulder of Orion."